Surface-Treated Pellethanes: Comparative Quantification of Encrustation in Artificial Urine Solution

Abstract

Introduction: Encrustation of implanted urinary tract devices is associated with significant morbidity. Pellethane Ò is a polyether-based compound noted for its strength, porosity, and resistance to solvents. We assessed Pellethane thermoplastic polyurethane (TPU) with and without surface coatings 2-hydroxyethyl methacrylate (HEMA) and tetraethylene glycol dimethyl ether (TETRA) for the potential to resist encrustation in an artificial urine environment. Materials and Methods: Samples of Pellethane TPU, HEMA Pellethane TPU, TETRA Pellethane TPU, and hydrogel-coated ureteral stent (Cook Ò) were suspended in a batch-flow model with an artificial urine solution (AUS). Every 48 hours for 90 days, 40% of the solution was replaced with fresh AUS. All samples were stored in a 37°C incubator. Subsequently, the samples were thoroughly dried for 48 hours before weighing. Scanning electron microscopy was used to assess the degree of encrustation. Nu-Attom Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine the precise compositions of the encrustation specifically with regard to calcium, magnesium, and phosphate. Results: At the conclusion of the 90-day trial, the samples were analyzed, and the average mass changes were as follows: stent 63.78%, uncoated Pellethane TPU 11.50%, HEMA-coated Pellethane TPU 2.90%, and TETRAcoated Pellethane TPU 0.60%. Pellethane TPU products, and specifically those coated with HEMA and TETRA, exhibited less average mass increase and a lesser propensity to form encrustation than the traditional urinary tract stent. The mass increases noted on coated Pellethane devices were primarily ionic, whereas that of the stent was not. Conclusion: Pellethane, particularly with an HEMA-based preventative coating, may serve as a favorable alternative to traditional urinary stent material, providing its improved resistance to encrustation.

Current material engineering strategies to prevent catheter encrustation in urinary tracts

“…The result show that after 90-day trial, all the average mass of magnesium, calcium, and phosphorus were as follows: stent 0.067 ​mg, 0.312 ​mg, 1.149 ​mg, pellethane TPU 0.022 ​mg 0.164 ​mg, 0.348 ​mg, HEMA coated pellethane TPU 0.006 ​mg, 0.052 ​mg, 0.360 ​mg and TETRA-coated pellethane TPU 0.027 ​mg, 0.183 ​mg, 0.530 ​mg. Compared with traditional urinary device material, HEMA-coated pellethane TPU has better anti-encrustation performance [ 89 ]. The ant-encrustation effect of HEMA-coated pellethane TPU in vitro experiments for up to 90 days also shows that it is very suitable for patients with long-term indwelling catheters/stents.…”

A novel biodegradable ureteral stent with antibacterial ability to inhibit biofilm formation

“…Although ureteral stents have been a routine procedure in urological surgery for decades, many problems remain. Infection and encrustation are the main causes of stent failure in recent studies 4,15,19 . When infection occurs, encrustation becomes severe due to the urease-producing bacteria which elevating pH of urine and the solubility of crystalline salts reduced as the result 20 .…”

“…Antibacterial or antibiofilm strategies for ureteral stents involving hydrogel coating, antibiotic coating or coating with antimicrobial agents are currently under investigation 19,[26][27][28][29][30] . However, the disadvantage of the coating is obvious, that is, it is easy to fail with the degradation process.…”

“…Antibacterial or antibiofilm strategies for ureteral stents involving hydrogel coating, antibiotic coating or coating with antimicrobial agents are currently under investigation. 19,26–30 However, the disadvantage of the coating is obvious: that is, it easily fails with the degradation process. Therefore, we need to design a ureteral stent that can overcome the degradation process and be effectively antibacterial from beginning to end.…”

“…Infection and encrustation were the main causes of stent failure in recent studies. 4,15,19 When infection occurs, encrustation becomes severe due to the urease-producing bacteria which elevate the pH of the urine, resulting in a reduction in the solubility of crystalline salts. 20 Therefore, it is critical to solve the problem of infection caused by bacteria.…”